Glycyrrhizin, a saponin of licorice root, its aglycone, glycyrrhetinic acid, and their soluble derivatives have an excellent antiinflammatory effect, and their pharmacological effects as medicines for peptic ulcer and allergic disorders have been highly evaluated clinically. However, their administration in higher dosages for a long period results in so-called pseudoaldosteronism such as hypertension, hypopotassemia, and edema owing to abnormal metabolism of electrolytes. Therefore, the use of these medicines is regulated in the amounts to be administered.
The present inventors, Shibata, Kumagai and others, assumed that the foregoing aldosterone-like action (side effect) of glycyrrhetinic acid is ascribable to the fact that glycyrrhetinic acid inhibits the activity of .DELTA..sup.4 -5.alpha. and 6.beta.-reductase, which performs metabolism of aldosterone in the liver, leading to enhancement of the activity of aldosterone; thus, the present inventors have made assiduous investigations in order to obtain a compound which can reduce or remove the aldosterone-like action (side effect) of glycyrrhetinic acid and yet retain or enhance characteristic physiological activities of glycyrrhetinic acid. The present inventors have now found that olean-12-ene-3.beta., 30-diol is the most appropriate as a compound which can achieve the objective. Accordingly, this compound olean-12-ene-3.beta., 30-diol is devoid of side effects of glycyrrhetinic acid and yet shows excellent results, as seen from experimental results in examples (B, C, and D) hereinafter provided, in tests for antiulcer, antiinflammatory, and antiallergic activities. The preparation of the compound olean-12-ene-3.beta., 30-diol, has been described by L. Canonica et al.; Gazz. Chim. Ital., 97, 1347 (1967) and by Ryabinin and Konovalova Zh. Obshch. Khim. 32, 644 (1962). Such a process is shown in Chart 1. ##STR1##
The process shown in Chart 1 involves complicated steps in which expensive platinum oxide is used. Further, in the process, an unchanged starting material is incorporated in intermediates to make the separation and purification of the intermediates difficult and hence the yield thereof is low. Therefore, the process is scarcely feasible and suffers from a great disadvantage that mass production is impossible. The present inventors have made assiduous investigations in order to remove these drawbacks of the known process. As a result, the present inventors have now succeeded in developing a new and useful process which satisfactorily meets requirements for industrial mass production, that is, a process in which production steps are simple and safe, and the production cost is low.